Open circuit respiratory apparatus



Nov. 4, 1958 E; GAGNAN OPEN CIRCUIT REsIRAToRY APPARATUS 2 sheets-sheet4 1 Filed March 31, 1955 l2 Sheets-Sheet 2 E. GAGNAN OPEN CIRCUIT RESPIRATORY APPARATUS f/.f 75o /Jl /Js 15J /52 5/ 115 l Nov. 4, 1958,

Filed March 31;' 1955 United States Patent 2,858,829 OPEN CIRCUIT RESPIRATORY APPARATUS Emile Gagnan, Montreal, Quebec, Canada, assignor to La Spirotechnique, Societe Anonyme, Paris, France Application March 31, 195s, serial No. 498,367 13 claims. (C1. 12s- 142) The present invention is related to open circuit respiratory apparatus for use in a non-breathable atmosphere or for under water diving. v

In a known type of such apparatus, the breathable gas, air, for instance, is compressed under a high pressure in a cylinder and delivered to the user b y means ofv a pressure regulator. It is subsequently exhausted into the surrounding medium outside by the user through an exhaust valve. Usually, the regulator supplies the air in response to the inhalation of the user acting on the diaphragm of the apparatus.

The present invention aims to provide a device of this nature which allows air to be supplied to the user at a pressure higher than that supplied by a depression regulator, while allowing the expiration of this air at a pressure lower than the supply pressure. The respiratory air volumes are thus blown in and expirationtakes place without the least sensation of effort, the, result being a great ease of breathing, particularly appreciated by divers. .v

In order to obtain this result, the apparatus according to the invention utilizes a stored volume of\ compressed gas which is fed into a regulator similar to those of usual apparatus, but in which the diaphragmisfsubjected to the action of a variable action device the thrust of which upon said diaphragm decreaseswhen the latter moves away from its operative position forndn'ving-the delivery valve of the regulator, means being provided for controlling the expiration ap of the respiratory circuit so as to close it while the yregulator is delivering fresh air. i i

Other features and advantages of the 'inventionwill appear from the following description ofthree embodiments of a respiratory apparatus represented, by way of example only, in the appended drawings, in which: 'f

, Figure 1 is an axial section of a regulator with its diaphragm in the' position of release of the exhaust valve ap or. expiration position. A ""-i- Figure 2 is a view, similar to :Figure 1, Abut with the diaphragm in the air intake or inhalation position, *the exhaust valve ap lbeing locked.

-Figure 3 is a partial axial section of thev expander through a plane perpendicular to the section planeof Figure 1.

' Figure4 is a view similar to Figure 3, but corresponding in location to Figure 2. v Figure 5 is a plan view of one preferred embodiment of the spring used in the apparatus of Figures 1 to 4.

Figure 6 is an axial section of an alternative construction of the regulator assemblyl of a respiratory apparatus, the exhaust. valve ap of which isvj'lo'cated on the diaphragm, the elements of thisregulator being'rep-- resented in the relative positions which 'correspond to ICS modification of the exhaust valve ap and its locking device during an air intake or inhalation phase.

The regulator used in the open circuit respiratory apparatus of the general type considered -and represented in Figures 1 to 4 comprises, as some devices of this type, a casing formed of two portions 1 and 2, between which there is tightly clamped a llexible diaphragm or deformable membrane 3, the motions of which control an air intake ap valve 4 in the channel supplying air to the user.

In the construction shown, the valve tlap 4 is disposed at the outlet end of a irst stage regulator which is adapted 4to supply air under pressure from a high pressure cylinder (suitably connected to the intake end 5 of the regulator) at a pressure between the pressure of air in the cylinder and the inhalation pressure of the user. The valve Hap 4 is mounted on the end of a lever arm 4a pivotally mounted as indicated at 4b and is normally resiliently biased into closing'position by a spring 4c.

.The other end of the lever arm 4a is in the path of the centre of the regulator diaphragm 3 so that flexure of the diaphragm by inhalation of the user acts to open the valve ap 4.

The rst stage regulator shown is mounted in the upper portion 1 of the casing and consists of a valve 6 which is controlled by a diaphragm 7. The valve 6 includes a stem 6a which contacts the diaphragm 7 and the diaphragm 7 is subjected on the outer face to the thrust of a spring 8 and to the pressure of the air in the inhalation chamber 9.

A suitable connection, not illustrated, is provided to the` casing and is connected to the exhaust ap valve 11.-

As shown, the diaphragm 3 seals oi the inhalation chamber 9 from the lower casing portion 2 and the lower casing portion 2 is provided with a plurality of openings 12' so that the pressure of the surrounding water, when the apparatus is in use, acts on the lower surface of the diaphragm.

In accordance with the present invention, the diaphragm 3 is subjected, on its outer face, not only to the `pressure of the surrounding water but also to an additional variable thrust caused by a spring, for instance, and adjusted so as to deliver the air to the respiratory tracts of the diver at a pressure higher than that of the surrounding water at the average level of the lungs, for transforming-the inhalation into a forced in-blowing. During this in-blowing of air at these higher pressures, means are provided to retain the exhaust ap valve 11 in closed condition to avoid air loss to the outside.

In a preferred construction, the lips of the exhaust ap 11, which are of the duck bill type, are engaged between the bottom cross-member of the yoke 12, suitably secured on the bottom of the lower casing portion 2, and a plate 13 supported by a flexible blade 14 abutting at its two ends against the flanged ends 12a of the arms or sides of the yoke 12. The flexible blade 14 acts as a spring for moving the plate 13 away from the cross-member of the yoke 12, the motion being limited by the abutting of the ends 13a of the plate against the anges 12a of the arms of the yoke 12. Downward pressure of the plate 13 squeezes the lips of the flap 11 against thelower member of the yoke 12 and so maintains the exhaust flap 11 in closed condition.

The fplate' 13 and the exible blade'14 which carries it are coupled with an elastic blade 15, the two ends of which areL connected with the ends of a st irrup 16 suitably securedlto the outer face of the diaphrag'nS. The overall" length` of the (blade 15 is greaterftha'nnthe distance between its connection points 17 tothe `stirrup 16.31.16, therefore, it is flexed or bent into an arcuate shape.

The coupling between the blade and the plate 13, in the construction `shown, is ensured :simply :by .alclip 18 which .connects the Imid .point of :the blade 15 -svith the mid point ofthe blade 14. .Both these bl-ades 114 and 15, are of -resilient material; forexampleptheyfmay conveniently consist of resilient :metal .wire such as a piano wire, shaped, .as shown in Eigure 5, .into v.loops lying in one plane .when free, the distance D being greater than the distance between .the attachment points 17 on thecorresponding stirialp 16.

The operation of this arrangement is as follows:

Figure .l corresponds to the vcase .when the diver .has just breathed .out :into .the water and the pressure in chamber r9 has Ybecome'suhstantially equal to the pressure of the surrounding :water at thecentre of thrust of .the outer face of the diaphragm 3. 'The diaphragm 3 is shown in a .position `wherein the intake flap valve 4 is closed, and the blades or springs 14 and 15 occupy positions in which no appreciable resilient action is excrted on the diaphragm 3. vThe tension of the blade 14 overcomes that of the blade 415 (which is low, due to its `attening.) andthe flap I11 :is released by the raisin-g of .the-plate 13. The result is --that expiration is effected normally through the flap 11, no overpressure being caused by the diaphragm When `the user starts to 4breathe i1i,see Figure 2, the depression created :in the chamber 9 depresses the diaphragm 6 inwards, the points 17 being carried along in this motion, and the clip 1 8 Vheld by the plate .13 remaining tixed. As a result, the blade 15 initiates a curvature reversal and begins to push against the Vclip 18 CII withian .increasing force, whichhas the result of causing the regulator to deliver air under an overpressure corresponding to this value increased by the reaction from the blade 15, the .exhaust ap 11 being locked. This is overpressured in-breathing phase corresponding to Figure 2.

At the end of this phase, the user, .by slightly forcing his expiration instigat-es the return motion of the diaphragm 3 towards the plate 13. As soon as this motion has been started, the eifective thrust of the blade 15 on the diaphragm decreases with the attenuation of its curvature. This causes an accentuation of the initiated motion which is accelerated by Vthe instability of the equilibrium obtained- The diaphragm 3 is suddenly pushed back and the plate 13 is again applied onto the flap 11 as soon as the thrust of the blade 15 overcomes the tension of the blade 14. The position is restored to that of Figure 1 and the expiration goes on with the complete drop of any overpressure in the .respiratory circuit. The cycle of operations is then repeated at every stroke of in-breathing and expiration of the user.

In the alternative construction shown in Figures 6 and 7, the regulator is of the type having a single eX- pansion stage. The source of air at high pressure is connected to the threaded end piece 105 of a block 120 secured by a nut 121 to the bottom of the portion 100 ofthe casing. The air arrives through the duct 122 and its ow is controlled by a needle valve 104 suitably guided in the block 120. This Valve 104, is controlled by levers 123 which are subjected directly to the thrust of the diaphragm 103 of the regulator and which have their fulcrums on their block 120. These levers, for instance, and as shown, are subjected to the thrust oi a spring 124 which keeps their inner ends in contact with parts 126 secured to the inner face of the diaphragm 103. This spring biases the needle valve 104 in its closing direction. The air delivered when the needle valve 10.4 is. open is led through a tube 127 to l.the vpipe .110 `,connected `with the `flexible hose Aleading to the mask or to the users mouthpiece. The pipe is not in direct communication with the chamber 109 of the regulator adjacent the inner face of the diaphragm 103 and the air exhausted is brought back to this chamber 109 through a tube 128 in such a way that the air delivered into the pipe 110 does not mix with ,the Y.expired gases and the user vonly breathes pure air.

"The top portion '102 tor cover of the casing is secured on the portion 100 by any suitable means and tightly retains theperipheryof the diaphragm 103 the central portion of which is reinforced by a rigid disc 129, provided with holes 130 and which constitutes the seat for the expiration ap 111. This ap may be formed of a flexible rubber disc for instance, and it may be locked on its seat for closing the holes 130, by a plate 131, thchub ofwhich'isfguided axially by a pin 132 attached to :the centre :of -.the disc 129. The maximum spacing between the plate 131 and the fap 111 is adjusted by a :stop .-and, for instance, .by :a flange 133 formed at thezend of lthe pin 132. The plate v131is biased in .the direction away vfrom the ydisc 129 by a spring 134. It 'is coupled, fon/.the Vother hand, with lthe mid pointof a ispring 'i115 :consisting Aof a blade for preferably an elastic metal wire such=as shown in Figure 5 and described above. "This spring iis mountedrbetweentwo vfixed points constituted, in the construction shown, bythe grooves .117 provided by folding the arms of a stirrup .116 secured on the bottom of the portion 102 of the casing .of fthe regulator, -the distance between .the grooves ll171being less than'the length 'Dof the spring 115 when `free. The coupling ,of the-spring 115 and plate 131 for locking lthe ap 111 is eiected, 'for instance, by -forcing the .branches .of its central loop vinside a groove `of a knob 135 provided Von-.the fhu'b Aof .fthe plate .131.

The ends of the arms of the stirrup 116 constitute stops for limiting the ,displacements of the diaphragm 1'03 @towards tthe bottom :of :the casing 'portion 102, lor upwards, in fthe construction vshown -in the drawings.

The operation is yas follows: The .relative positions :of fthe elements represented .in Figure .6 correspond .to .the .expiration phase. The -diaphragm 103, subjected on its .outer -face to the pressure of. .the surrounding :medium which acts through ythe holes -112' .of -the casing portion -102 has been `pushed back Aby the expiration thrust and the .spring 115 has been pushed back towards the bottom of the casing portion '102; the plate 131 is -moved away by the spring 13:4 of -lthe exhaust ap y111 'which is released andthe use rbreathes .out normally through the pipe 128 and orices 1 30 y and 112'. At the end of 'the expiration, the user starts a depression which closes the flap 111 and .causes .a displacement of the .diaphragm 103 in the opening direction of the needle valve 104. This displacement of the diaphragm 103 is transmitted to the mid point ,of the spring 115 by the pin 132 and .knob and when the spring .-115 is sufficiently bent it applies `to the plate. 131 `a :thrust which is suflicient for Aapplying it in the lflap 111 by overcoming the reaction of the spring 134. The exhaust ap 111 is locked and, through the levers 123, the needle valve 104 is opened and delivers air at 'a pressure which is determined vby the valve of the thrust caused by the spring 115. The components o f the apparatus are then in the positions represented in Figure 7.

.At `the endof the inhalation phase., the user stops inhaling and'begins a new `expiration phase by initially accentuating the forcing back effect of the gases which he, @Khausts into the regulator. The diaphragm 103 is displaced in the direction for shutting the needle valve 104 and when the thrust of the spring 134 exceeds :that of the spring 115 the plate 131 moves suddenly away' from the liap 111 and all the elements resume the positions they occupied in Figli-reo and which correspond to an xpirationphase. The operating cycle described above is repeated. j

In the further modiedembodiment represented in Figure 8, the spring. 134 hasbeen omitted, which, in the case of the constructions shown in Figures 6 and 7, tends to move the plate 131 away from the disc 129. In the construction shown in Figure 8, the stop which limits the relative spacing of these two elements is constituted by lugs 133' suitably secured on the disc 129. In this modied embodiment, use is made of the point of the stroke of the centrek ofthe spring 115 where the reversal of the direction of thrust of this spring takes place. When the user holds back his inhalation for starting the expiration phase,- the diaphragm 103'is pushed 'upwards and the camber of the spring 115 is reversed :as well as the force it applies to the plate 131;. the latter is moved away from the disc 129- thereby releasing 'the exhaust ilap 11 which opens for the expiration phase.

At the end of the expiration, the suction exerted by the inhalation of the user causes a downward displacement of the diaphragm 103 and the reversal of the camber of the spring 115 and of the direction of the.

force it exerts on the plate 131; the latter is applied on the disc 129 and locks theexhaust flap 111, the diaphragmf103 regulating the air delivery according to the pressure required.

What I claim is: l. In an 'open circuit breathing apparatus of the type having a presurel regulator including an inner chamber, an inlet valve in said chamber for a breathable gas fed from a pressure source, valve controlling means mounted in said regulator including a ilexiblev diaphragm having an outer face subjected to the pressure of the medium surrounding the regulator, an exhaust valve mounted in said regulator adjacent the exterior surface of said diaphragm, an air intake connection extending from vsaid regulator chamber to a mouthpiece and an exhaust connection extending from said mouthpiece to said exhaust valve, a resilient variable action means mounted in said regulator adjacent to and in operative connection with said diaphragm and exhaust valve adapted to apply a supplemental forc'e to said diaphragm and a closing force to said exhaust valve during movement of said diaphragm .in the direction opening said air valve and a quick reverse force to said diaphragm and release of said exhaust valve during movement of said diaphragm in the opposite direction, whereby air is caused to be delivered to the user at a pressure higher than the pressure of the medium acting on said diaphragm and is exhausted through said exhaust valve by the user at a pressure lower than said air delivery pressure.

2. In a breathing apparatus as claimed in claiml wherein said exhaust valve is disposed in spaced apart relationship from said diaphragm and said variable action means comprises a cambered resilient spring disposed between said diaphragm and exhaust valve, said spring being connected to said diaphragm and also to valve closing means disposed in operative engagement with said exhaust valve.

3. In a breathing apparatus as claimed in claim 1 wherein said exhaust valve is mounted on said diaphragm and said variable action means comprises a cambered resilient spring connected to said exhaust valve.

4. In a breathing apparatus as claimed in claim 2 wherein said cambered resilient spring consists of a flat blade of resilient metal mounted adjacent to and centrally of said diaphragm between two spaced apart retaining members in a normally arcuate shape with the connection to said valve closing means located centrally of said blade.

5. In a breathing apparatus as claimed in claim 2 wherein said cambered resilient spring consists of an elongated length of resilient metal wire shaped into parallel loops forming a at resilient band, said band being mounted adjacent to and centrally of said diaphragm -be'tween two spaced apart retaining-members in a `normally arcuate shape with the connection to said.

an inner chamber, air inlet valve in said chamber for a breathable gas fed from a pressure source, yalve controlling means mounted in said regulator including a ilex-l ible diaphragm having an inner faceforming one wall of said inner chamber and an outer face subjected to the pressure of the medium surrounding the regulator, a apper type exhaust valve mounted on said regulator casing adjacent the outer surface of and in substantial alignment with said diaphragm, air intake and exhaust connections from a mouthpiece to said regulator inner' chamber and exhaust valve respectively, a supporting stirrup havingspaced apart terminal arms mounted on said diaphragm outer face, an elongated resilient mem-.

ber mounted between the arms of said stirrup whereby it is retained in a tensioned arcuate form, a flanged yoke mounted in said casing with the flanges disposed each side of said exhaust valve-and a pressure plate mounted for sliding movement between'said yoke anges and extending over said exhaust valve, a resilient at spring connected centrally to said pressure plate with the terminal ends bearing on said yoke flanges, and a connecting member between said at spring and the centre of said bowed elongated resilient member supported by said diaphragm, whereby dellection of said diaphragm in one direction by inhalation of the user and the pressure of the surrounding medium is augmented by the resilient tensioned action of said elongated member to apply an increased deflecting force to the diaphragm and the further bowing of said elongated member forces said flat spring in a reverse arc against said pressure plate closing said exhaust valve, and during expiration the pressure within the inner chamber against the diaphragm deects the diaphragm in the opposite direction and augmented through the reflex of said tlat spring, the arc of said elongated member is reversed releasing said exhaust valve allowing expiration of air at a pressure lower than the pressure at which it was delivered to said inner chamber.

8. In an open circuit breathing apparatus as claimed in claim 7 wherein said elongated resilient member comprises a flat spring.

9. In an open circuit breathingapparatus as claimed in claim 7 wherein said elongated resilient member comprises a length of resilient metal wire formed in parallel Endlating loops forming a substantially flat resilient l0. In an open circuit breathing apparatus of the type having a pressure regulator including a casing having an inner chamber, an inlet valve in said chamber for a breathable gas fed from a pressure source, valve controlling means mounted in said regulator including a flexible diaphragm having an inner face forming one wall of said inner chamber and an outer face subjected to the pressure of the medium surrounding said regulator, said diaphragm including at least one opening constituting an exhaust gas passage from said inner chamber, an exhaust ap valve mounted on said diaphragm and controlling the passage of exhaust gas through said diaphragm, flap controlling means mounted on said diaphragm over said exhaust ap, a supporting yoke having spaced apart arms mounted in said casing above and in alignment with said exhaust flap controlling means, an elongated resilient variable action member kmounted between said yoke arms `in a tensioned arcuate formation and being connected centrally of its'lengthto said flap controlling means, and air intake and exhaust connections from a mouthpiece to said air inlet valve and inner chamber respectively, whereby inhalation ofthe user acts to ex the #diaphragm in one valve opening direction vand the valve opening action of the diaphragm under the pressure of the surrounding medium Ais resiliently increased by said resilient member while the resilient member is bowed so vas to depress thesaid 'flap controlling means to retain said iiap in closed condition, and lupon expiration, the-diaphragm is -iiexed in the opposite direction so as to reduce and suddenly reverse vthe curvature of said resilient member raising said vexhaust ilap control means allowing expiration of `air at a pressure lower than the pressure at which it was yde livered from said air inlet valve.

11. In an open circuit breathing apparatus as claimed in claim 10 wherein said exhaust flap Acontrolling member is resiliently biased away from said flap by a cambered spring disposed between said exhaust ap and ap controlling member.

12. In an open circuit breathing apparatus 'as claimed i-n claim 10 wherein said elongated resilient member comprises ya length of resilient metal wire formed in parallel undulating loops forming a substantially flat resilient band.

13. In an open circuit breathing apparatus of 'the type having a pressure regulator including an inner chamber, an inlet valve in said chamber for a breathable gas fed from a pressure source, valve controlling means mounted in lsaid 'regulator including a exible :diaphragm shaving an outer face subjected to the pressure of the-medium surrounding the regulator, anexhaust valve vmounted kin said `regulator Aadjacent rthe exterior fsurface of 'said diaphragm, an 4airintake connection-extending from KVsaid regulator/chamber toa mouthpiece and anexhaust 'connection extending fromisaid mouthpiece to said exhaust valve, va tr'st Iresilient 'variable action member 'mounted in said regulator adjacentto and in operative connection with said diaphragm andfa second resilient variable member in operative connection l'with said exhaust valvejsaid rst vand -second resilient-variable "action members being exed in one -direction "by the movement of said di aphragmiin the :inhalation phase to add a supplemental force to -the inlet valve'ope'ning action of said diaphragm, and by its connectiontsaid yirst resilient member flexes said second resilient memberin'anexhaust valve closing direction, land in the -initial 'reverse 'movement of said diaphragm in the exhaust phase 'said :flexed second `resilient member overcomes the resilient action of said rst member and quickly reverses -itsflexure to augment-the exhaust valve opening movement of 'said diaphragm, whereby air is caused -to be delivered to the user at ya pressure higher -than the Vmedium acting on said diaphragm and isex'hauste'd through-saidlexhaust valveb'y the user at a pressure lower than said air delivery 'pressure.

Referencesv Cited in the 'le 'of this patent UNITED SVTTES YPATENTS 2,453,475 Tobias Nov. 9, "1948 

